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authorJohn Ogness <john.ogness@linutronix.de>2022-11-16 19:21:45 +0300
committerPetr Mladek <pmladek@suse.com>2022-12-02 13:25:02 +0300
commit7c2af0f634f1bc761ca827310dc7e8e586af502f (patch)
tree02cf4fbe0f84214aa148c8acc27ef47ac49de535 /drivers/tty
parent6f8836756f3cbb02bfd1f0e033516585250318a9 (diff)
downloadlinux-7c2af0f634f1bc761ca827310dc7e8e586af502f.tar.xz
tty: tty_io: use console_list_lock for list synchronization
show_cons_active() uses the console_lock to gather information on registered consoles. It requires that no consoles are unregistered until it is finished. The console_list_lock should be used because list synchronization responsibility will be removed from the console_lock in a later change. Note, the console_lock is still needed to serialize the device() callback with other console operations. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-34-john.ogness@linutronix.de
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_io.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index ee4da2fec328..cafdff575716 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3527,16 +3527,13 @@ static ssize_t show_cons_active(struct device *dev,
ssize_t count = 0;
/*
- * Hold the console_lock to guarantee that no consoles are
+ * Hold the console_list_lock to guarantee that no consoles are
* unregistered until all console processing is complete.
* This also allows safe traversal of the console list and
* race-free reading of @flags.
- *
- * Take console_lock to serialize device() callback with
- * other console operations. For example, fg_console is
- * modified under console_lock when switching vt.
*/
- console_lock();
+ console_list_lock();
+
for_each_console(c) {
if (!c->device)
continue;
@@ -3548,6 +3545,13 @@ static ssize_t show_cons_active(struct device *dev,
if (i >= ARRAY_SIZE(cs))
break;
}
+
+ /*
+ * Take console_lock to serialize device() callback with
+ * other console operations. For example, fg_console is
+ * modified under console_lock when switching vt.
+ */
+ console_lock();
while (i--) {
int index = cs[i]->index;
struct tty_driver *drv = cs[i]->device(cs[i], &index);
@@ -3563,6 +3567,8 @@ static ssize_t show_cons_active(struct device *dev,
}
console_unlock();
+ console_list_unlock();
+
return count;
}
static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);